I wish these 5v USB batteries were around and cheap back in the JB3 days! Back then, I had a Marc Kim aka Leegeddy "Voltage Regulator Box" that took a 12v or 9v or 6v power source[can't remember] like an SLA[this was 2004-2006 mind you, so this was SLAs were still cheapest and most reliable power back then], and its stepped down the voltage to 5v for the JB3! That way, from one battery, I could power BOTH my V3@6v/9v/12v, and the JB3@5v, since it had dual outputs! I could've run a MUCH smaller USB battery for my JB3 and my v3 from the 6v SLA, but that would make two separate batteries Still much smaller than the HUGE 12v SLA that I had for Phish Summer Tour 2004, which would power my v3 AND JB3 for like 24+ hrs straight